Buying in the dip is not a bad idea or thing to do, Because dip is an opportunity for one to accumulate more coin, what is bad is always waiting for a dip before you can accumulate especially if it's Bitcoin you are investing in, some people that are accumulating Bitcoin only do that when there's a dip and that strategy will delay you if you are accumulating and holding for a long term, if you are constantly waiting for a dip to happen in Bitcoin you may not accumulate enough Bitcoin, waiting for a dip to happen before you can invest is a delay strategy and should be stopped.
What you should do if you want to take advantage of any dip that happens is to have a strong reserved funds so any time at all a dip happen you can just dip hands into your reserved funds and buy and still continue with your DCA strategy.
It is very good we encourage investors to always have a good reserved funds and also an emergency funds, this two are very important in it comes to bitcoin investment, when you don't have them in place it will cause you to lose some of your Bitcoin, for example emergency funds it helps during emergency period when you don't have money on you anymore you can dip hands into your emergency funds instead of your Bitcoin investment.
Some people don't take advantage of the dip and they panic when there's a dip, and some people will not have funds to accumulate in the dip and this is one major thing that stop people from taking advantage of the dip and that is why having a reserved funds is important when you have it you will always take advantage of any dip that comes.